Coal power plants use enough water to supply the needs of 1 billion people and that will almost double if all the world’s planned power plants come online.

Almost half the new power plants will be built in areas that are already in high water stress, a report commissioned by Greenpeace says.

“We now know that coal not only pollutes our skies and fuels climate change, it also deprives us of our most precious resources: water,” said Harri Lammi, a Greenpeace campaigner.

The research, released on World Water Day, examined the water usage of each of the world’s 8,359 existing coal power plants, as well as of all the proposed power plants that could be identified. It combined the water used in producing the electricity, as well as that used in mining the coal.

The European Union and eight OECD countries have agreed to reduce state aid for coal-fired power stations in developing countries. But many stations will be exempt from the cuts. EurActiv France reports.

The research found 44% of current plants, and 45% of planned coal power plants, were in areas that were in a state of water stress – where water use is already considered to be having significant ecosystem impacts.

And about a quarter of the proposed new coal plants were planned in regions that were already running a freshwater deficit, where water is used faster than it is naturally replenishing – areas that Greenpeace put on a “red list”. That figure was largely driven by China, where most of the world’s coal is used and almost half of the proposed coal fleet was in red-list areas. India and Turkey were next, each with 13% of planned coal power stations set to be in red-list areas.

The research uses more precise data, and provides more in-depth findings, but is broadly in line with figures released by the International Energy Agency in 2012, suggesting the amount of water used in electricity generation would increase by 85% between 2010 and 2035.

Balkan countries and Ukraine are making “substantial investments” in polluting coal power stations to sell cheap electricity to the European Union, as the bloc searches for new suppliers to reduce its dependence on Russian gas.

Greenpeace concluded that coal expansion in “red list” areas should simply not go ahead. It also called for existing plants in those areas to be phased out and replaced with renewable energy like solar panels and wind.

It called for coal-fired power plants that are more than 40 years old to be shut, since they were often the least efficient. The country that would save the most water by doing that was the US, the report found, saving 74% of the water used by the industry and 76bn cubic litres of water.

“Governments must recognise that replacing coal with renewable energy will not only help them deliver on their climate agreements, but also deliver huge water savings,” said Iris Cheng of Greenpeace, who is the lead author of the report.

“It’s more urgent than ever that we move towards a 100% renewable future.”